End mill breakage detection using mean frequency analysis of scalogram

The condition of cutting tools is of particular importance for an efficient milling process in any metal cutting process to prevent additional costs and unscheduled downtime. This paper presents the use of the mean frequency of a scalogram to end mill defect detection under varying feed rates. The metal cutting experiments were performed on a mild steel workpiece using a four-flute end mill, and resulting vibration of the cutting process detected from healthy and faulty cutter is considered for the analysis. It has been found that the feed rate is significantly influential upon the mean frequency of a scalogram, and mean frequency variation is quite responsive to the presence of fault even when the severity of fault is considerably small. Besides this, a trend indicator is defined to reflect the progression of fault severity and has been found to be very sensitive to not only the presence of fault, but also any change in the feed rate particularly when the severity of fault is small.